Growth and development of ‘sweet net 9’ melon (<i>Cucumis melo</i> L.) in NFT hydroponics as affected by pruning leaves below fruits and foliar application of potassium sulphate (K2SO4)

Leaf pruning reduces resource competition, directing assimilates to fruit development, while aging plants require supplemental K to support nutrient uptake. This study aimed to evaluate the effects of pruning leave below fruits and foliar application of K₂SO₄ on fruit weight and quality. The experiment was conducted over three months (October–December 2024) in a screenhouse at Pondok Pesantren Aqwamu Qila, Bantul, Yogyakarta. Sampling and analysis were carried out at the Crop Production Management Laboratory, Faculty of Agriculture, Universitas Gadjah Mada. A split-plot design was used with two factors, namely K₂SO₄ concentrations (0, 1, 2, 3 g/L) as the main plot and pruning (with/without) as the subplot, resulting in 8 treatment combinations replicated in 3 blocks. Data were analyzed using split-plot ANOVA in R-Studio, followed by DMRT at a 95% confidence level when significant differences were found. The study showed that pruning significantly increased leaf length (16.49%) and width (20.89%). The application of 0 g/L K₂SO₄ produced the highest harvest index (0.49), though not significantly different compared to that of 2 g/L and 3 g/L. Combining leaf pruning with 2 g/L K₂SO₄ resulted in a high leaf area and LAI (5.68), comparable to non-pruned plants with 3 g/L K₂SO₄ (5.83). This combination also yielded the highest fruit potassium content (1.90%) but lowered fruit sweetness (8.65 ˚Brix). The elevated potassium content may provide health benefits, particularly in reducing blood pressure.